Add Folder Thumbnail/Cover Image Support in Folder View

I have searched the existing feature requests, both open and closed, to make sure this is not a duplicate request. • Yes The feature Dear Immich maintainers, I’d like to propose a small but very handy addition to the recently released “Folder View”: Feature Allow each folder to display a user-selectable (or auto-selected) cover/thumbnail image, making visual navigation faster and more pleasant. Why it matters Large libraries often contain many folders with cryptic names (e.g. “2023-08-12”). A thumbnail instantly identifies the folder’s content. e.g:  and therefore lowers the migration friction for new users. Users who browse on mobile devices especially benefit from visual cues instead of reading tiny folder names. Thank you for the amazing work on Immich! Best regards Platform • Server • Web •…